Low Noise, Vibration
One problem for future SSTs, though, is restrictions on supersonic flight over land. Aerion says it will comply with the current rules by cruising at Mach 0.98 over the U.S. In other parts of the world where rules require that the boom can't reach the ground, Aerion can comply while flying as fast as Mach 1.1. Over the oceans, the ship can max out at Mach 1.6. Another contender, Supersonic Aerospace International, has a different plan, apparently hoping that the rules will evolve as technology improves. The company says its design, which it's working on together with Lockheed Martin's "Skunk Works," will be quiet enough to fly at Mach 1.6 and up anywhere in the world. The patented aerodynamic shape of the aircraft, including an inverted V-tail, will act to dampen the sonic wave. SAI's Quiet Supersonic Transport, or QSST, is projected to be ready for flight in 2011, with customer deliveries in 2013. The 12-passenger jet will cost $80 million.